Belectric USA used a Vermeer PD10 post driver to install 4,600 solar panel rack support posts for an Oregon solar power plant.

The initial plan called for completing a post every two minutes, but the PD10 was able to complete a post every minute increasing efficiency by 50%.

The Autoplumb feature on the PD10 can correct the post angle to complete verticality without manual adjustment.

The Vermeer PD10 pile driver utilizes an inclinometer with autoplumb and laser-controlled post-depth-control feature to help ensure that every post is installed to exacting specifications.

The challenge:

Install 20,000 solar panel rack support posts in the sandy soil of Oregon’s Great Sandy Deser

The players:

Belectric USA Constellation Energy

The process:

The Vermeer PD10 pile driver helped Belectric USA streamline the installation of commercial-sized solar panel grids. The contractor recently installed a 20,000-panel solar power plant just outside Christmas Valley, Ore., for project owner Constellation Energy. Although not the largest of the eight U.S. solar plants installed by Belectric to date, the multiple-stakeholder project will generate more than 5 megawatts (MW) of energy simply by harnessing rays of sun and converting it into sustainable, environmentally friendly energy.

The Constellation Energy solar field is situated in the heart of Oregon’s Great Sandy Desert. The site-— which receives more than 300 days of bright sunshine on average annually - encompasses more than 50 acres and is composed primarily of sagebrush and white sand of a consistency that Brad Thomas, project manager for Belectric, likens to talcum powder. The uneven, often-deceiving ground conditions made installing the 4,600 solar panel rack support posts a challenge in precision, accuracy and efficiency.

“Imagine walking across the surface of an area filled with flour and dotted by an occasional sagebrush plant. Not only is the appearance uneven and deceptive, the white powdery stuff gets into everything. It’s very desolate and isolated,” Thomas said.

“The posts are the stabilizing foundation of ground-mounted solar panel systems,” says Jon Kuyers, director of underground solutions for Vermeer. “The freestanding PD10 pile driver utilizes an inclinometer with autoplumb and laser-controlled post-depth-control feature to help ensure that every post is installed to exacting specifications. Since precision is a must, the PD10 pile driver will help to alleviate much of the guesswork involved with installing a large number of posts at any given site, while helping streamline the process more efficiently and accurately.”

The posts required 1/4-inch accuracy in the spacing and depth of each post; in surface conditions that could literally shift with the slightest gentle breeze. Prior to learning of the PD10 pile driver, Thomas’ crews would likely have relied on the same auger/pile driving method used in the past. The auger method is often specified in difficult ground conditions or at sites that may require a concrete base for added stability even though spoil displacement and disposal can present challenges. Another common approach is to attach a pile driver to an excavator-type implement - despite the fact that excavators are not designed for this type of application.

“Using GPS, our survey team pinpointed the exact locations for each of the 20,000 posts, based on our CAD drawings,” Thomas says. ”We used the PD10 pile driver because it can pick up the posts and drive them in accurately in a faster time. The machine’s ability to combine precision with speed of operation enhanced productivity. Initially, we had planned on completing a post every two minutes, but the PD10 was able to complete a post every minute. So we were able to improve our installation efficiency by 50 percent with the PD10 pile driver.”

The PD10 pile driver features an integrated control system display that allows the seated operator to view a variety of different machine functions including post angle on an x/y axis and post height. The Autoplumb feature can correct the post angle to complete verticality without manual adjustment, eliminating the need for a hand level to position the mast vertically. This feature helps reduce both cycle time and out-of-plumb posts. An optional laser receiver helps to ensure posts are installed on-grade and assists in keeping post height consistent.

“We really appreciate the computerization of the elevations,” Thomas says. “The machine stops exactly where it is programmed to stop. So if the height is supposed to be 4 feet above grade, the PD10 pile driver stops on that measurement precisely. Not only is the machine engineered to be fast, it’s also very accurate.”